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|
; $Id: bs3-cpu-state64-1-asm.asm $
;; @file
; BS3Kit - bs3-cpu-state64-1
;
;
; Copyright (C) 2007-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
;*********************************************************************************************************************************
;* Header Files *
;*********************************************************************************************************************************
%include "bs3kit.mac"
;*********************************************************************************************************************************
;* Global Variables *
;*********************************************************************************************************************************
BS3_BEGIN_DATA16
BS3_GLOBAL_DATA g_bs3CpuState64CtxCaller, BS3REGCTX_size
resb BS3REGCTX_size
BS3_GLOBAL_DATA g_bs3CpuState64CtxToLoad, BS3REGCTX_size
resb BS3REGCTX_size
BS3_GLOBAL_DATA g_bs3CpuState64CtxSaved, BS3REGCTX_size
resb BS3REGCTX_size
BS3_GLOBAL_DATA g_bs3CpuState64RCX, 8
dq 1
;*********************************************************************************************************************************
;* External Symbols *
;*********************************************************************************************************************************
BS3_BEGIN_TEXT64
EXTERN Bs3RegCtxRestore_c64
EXTERN Bs3RegCtxSave_c64
BS3_BEGIN_TEXT64
BS3_SET_BITS 64
;;
;; Test worker that switches between 64-bit and 16-bit real mode,
;; only trashing RAX, BX, DS, RSP (preseved) and RIP.
;;
;; Caller puts the state to load in g_bs3CpuState64CtxToLoad, this function alters
;; the BX and RIP values before loading it. It then switches to 16-bit real mode,
;; executes the worker given as input, re-enters long mode and saves the state to
;; g_bs3CpuState64CtxSaved.
;;
;; @param rcx Address of worker (16-bit) to invoke while in real-mode.
;;
BS3_PROC_BEGIN NAME(bs3CpuState64Worker)
push rbp
mov rbp, rsp
sub rsp, 40h
mov [rbp + 16], rcx
;
; Save the current register state so we can return with the exact state we entered.
;
lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxCaller)) wrt FLAT]
mov [rsp], rcx
call NAME(Bs3RegCtxSave_c64)
;
; Load the context. We modify the state to be loaded so that it fits
; into the code flow here..
;
lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxToLoad)) wrt FLAT]
mov [rcx + BS3REGCTX.rsp], rsp
;lea rdx, [BS3_WRT_RIP(.ctx_loaded) wrt FLAT] - absolute address cannot be relative. wtf?
mov edx, .ctx_loaded wrt FLAT
mov [rcx + BS3REGCTX.rip], rdx
mov edx, [rbp + 16] ; Worker address. Putting it in the BX register relative to 16-bit CS.
sub edx, BS3_ADDR_BS3TEXT16
mov [rcx + BS3REGCTX.rbx], dx
mov edx, 0 ; fFlags
mov [rsp], rcx
mov [rsp + 8], rdx
call NAME(Bs3RegCtxRestore_c64)
.ctx_loaded:
;
; Disable long mode.
;
; Construct a far return for switching to 16-bit code.
push BS3_SEL_R0_CS16
push .sixteen_bit_segment wrt CGROUP16
xRETF
BS3_BEGIN_TEXT16
BS3_SET_BITS 16
BS3_GLOBAL_LOCAL_LABEL .sixteen_bit_segment
; Make the DS usable from real mode.
mov ax, BS3_SEL_R0_DS16
mov ds, ax
; Exit to real mode.
mov eax, cr0
and eax, X86_CR0_NO_PE_NO_PG
mov cr0, eax
jmp CGROUP16:.reload_cs16
BS3_GLOBAL_LOCAL_LABEL .reload_cs16
;
; Jump to the 16-bit worker function that will make state modifications.
;
jmp bx
BS3_GLOBAL_LOCAL_LABEL .resume16
;
; Re-enter long mode.
;
mov eax, cr0
or eax, X86_CR0_PE | X86_CR0_PG
mov cr0, eax
jmp CGROUP16:.reload_cs_long_mode
BS3_GLOBAL_LOCAL_LABEL .reload_cs_long_mode
; Construct a far return for switching to 64-bit code.
push dword BS3_SEL_R0_CS64
push dword .sixtyfour_bit_segment wrt FLAT
o32 retf
BS3_BEGIN_TEXT64
BS3_GLOBAL_LOCAL_LABEL .sixtyfour_bit_segment
BS3_SET_BITS 64
;
; We're back in long mode, save the context.
;
mov [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64RCX)) wrt FLAT], rcx
lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxSaved)) wrt FLAT]
mov [rsp], rcx
call NAME(Bs3RegCtxSave_c64)
lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxSaved)) wrt FLAT]
mov rax, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64RCX)) wrt FLAT]
mov [rcx + BS3REGCTX.rcx], rax
;
; Load the caller's context.
;
lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxCaller)) wrt FLAT]
;lea rdx, [BS3_WRT_RIP(.return_sequence) wrt FLAT] - absolute address cannot be relative. wtf?
mov edx, .return_sequence wrt FLAT
mov [rcx + BS3REGCTX.rip], rdx
mov edx, 0
mov [rsp], rcx
mov [rsp + 8], rdx
call NAME(Bs3RegCtxRestore_c64)
.return_sequence:
add rsp, 40h
pop rbp
ret
BS3_PROC_END NAME(bs3CpuState64Worker)
BS3_BEGIN_TEXT16
;
; Real-mod modification workers for bs3CpuState64Worker.
;
BS3_PROC_BEGIN NAME(bs3CpuState64Worker_Nop)
nop
jmp NAME(bs3CpuState64Worker.resume16)
BS3_PROC_END NAME(bs3CpuState64Worker_Nop)
BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModAll32BitGrps)
mov eax, 0xc0ffee0d ; C code hardcodes these values too.
mov ecx, 0xc0ffee1d
mov edx, 0xc0ffee2d
mov ebx, 0xc0ffee3d
; leave esp alone for now.
mov ebp, 0xc0ffee5d
mov esi, 0xc0ffee6d
mov edi, 0xc0ffee7d
jmp NAME(bs3CpuState64Worker.resume16)
BS3_PROC_END NAME(bs3CpuState64Worker_ModAll32BitGrps)
BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModAll16BitGrps)
mov ax, 0xfad0 ; C code hardcodes these values too.
mov cx, 0xfad1
mov dx, 0xfad2
mov bx, 0xfad3
; leave esp alone for now.
mov bp, 0xfad5
mov si, 0xfad6
mov di, 0xfad7
jmp NAME(bs3CpuState64Worker.resume16)
BS3_PROC_END NAME(bs3CpuState64Worker_ModAll16BitGrps)
BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModAll8BitGrps)
mov al, 0x10 ; C code hardcodes these values too.
mov ah, 0x11
mov cl, 0x20
mov ch, 0x21
mov dl, 0x30
mov dh, 0x31
mov bl, 0x40
mov bh, 0x41
jmp NAME(bs3CpuState64Worker.resume16)
BS3_PROC_END NAME(bs3CpuState64Worker_ModAll8BitGrps)
BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModCr2)
mov eax, 0xf00dface ; C code hardcodes this value too.
mov cr2, eax
jmp NAME(bs3CpuState64Worker.resume16)
BS3_PROC_END NAME(bs3CpuState64Worker_ModCr2)
;; @todo drX registers.
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